
.wrapper{
    position:relative;
    width:400px;
    height:400px;
    margin:100px auto;
}
.wrapper .box{
    width: 100%;
    height: 100%;
}
.wrapper .box img{
    width: 100%;
}
.wrapper #button{
    width:130px;
    height:130px;
    position:absolute;
    border-radius: 50%;
    top: 50%;
    left: 50%;
    margin-top: -65px;
    margin-left: -65px;
}
.wrapper #button img{
    position: absolute;
    top:-23px;
    left:0;
    width:130px;
}